A review of the evidence from in vitro and in vivo studies for a role for phorbol ester tumour promoters from the Euphorbiales in the selection and clonal expansion of specific cell populations

Review of the evidence from in vitro and in vivo studies for a role for phorbol ester tumour promoters from the Euphorbiales in the selection and clonal expansion of specific cell populations. The identification of the active principle of croton oil as 12-0-tetradecanoylphorbol-13-acetate (TPA) and the advent of in vitro studies, facilitated the identification of a plethora of biochemical effects, certain of which could be correlated with biological and differentiation end points. Evidence is presented for the ability of TPA to select and expand specific cell populations in two different cell culture systems. The roles of differentiation state and second messenger systems will be discussed in relation to models of multi-step carcinogenesis.